1. Technical Field
The present invention relates to a method and apparatus for detecting moisture, and more particularly to a method and apparatus for detecting moisture in an electrically insulative portion of a body of mass.
2. Related Art
Large power generators can be water cooled by allowing the water to flow through the stator bars. Although this flowing water removes excessive heat, water leaks are common due to nearly a hundred stator bars in a mega-watt generator. The leaking water contaminates the electrical insulation, which surrounds the stator bar. These leaks can eventually cause a catastrophic failure. The ensuing failure could cause significant damage to the generator as well as lost revenue and customers may consequently experience loss of power or reduced power. Detection of moisture resulting from the leaking water at an early stage is therefore important for mitigating the effects of the leaking water. Some of the methods of detecting moisture in stator bars include visual inspection, gas leak testing, electrical hi-potting and capacitance mapping, each of which has disadvantages due to innacuracy and/or other difficulties. Thus there is a need for a more accurate and practical method and apparatus for detecting moisture at an early stage, wherein the moisture is due to water leaks in a power generator.